MON-448 Inflammatory and Oxidative Stress Parameters as Criteria of Classification of Metabolic Phenotypes of Insulin Resistance

In previous studies, we have shown that metabolic syndrome (MetS) and adult growth hormone deficiency (GHD) share different biochemical features, such as insulin-resistance (IR) but differ in antioxidant pattern. On the other hand, immunoglobulin free light chains (FLCs) are molecules with biological functions which are still incompletely known. In order to compare different populations with IR and, consequently, classify different phenotype of IR, we have evaluated FLCs and Total Antioxidant Capacity (TAC) in 3 groups of patients with IR due to different diseases: group A, patients with GHD (n=31, 24-69 ys, mean±SEM BMI 26.8±1.5 kg/m(2)); group B, patients with MetS (n=29, 29-70 ys, mean±SEM BMI 31.9±1.3 kg/m(2)); group C hyperferritinaemia (HF) (n=33, 28-78 ys, mean±SEM BMI 31.1±0.99 kg/m(2)). All patients underwent an oral glucose tolerance test; HOMA-IR was calculated; moreover, a morning blood sample was collected for evaluation of FLCs (assessed by turbidimetric assay) and TAC (assessed by spectrophotometric method, using the system H(2)O(2)-metmyoglobin, and expressed as Lag, latency time before the appearance of the radical form of the chromogen ABTS). HOMA-IR, as expected, was high in all three groups (group A 3.13±0.43, group B 3.16±0.28, group C 4.62 ±0.51), significantly higher in group C vs the other two groups. The parameters of inflammation and oxidative stress were significantly different in group A vs the other two groups (FLCs k 36.2±7.0 mg/l vs 15.4±0.9 in group B and 17.8±8.0 in group C; FLCs lambda 19.4±2.6 vs 11.3±0.7 in group B and 12.7±7.3 in group C; Lag 65.0±5.3 sec vs 82.9±6.2 in group B and 83.9±5.4 in group C). These data confirm that different mechanisms of oxidative stress and inflammation underlie these three subtypes of IR, and could be used to classify different phenotypes of these complex syndrome.